Apparatus for pumping and dialysis

Abstract

In medical apparatus, for example a dialysis machine, a pump in conjunction with a multichambered reservoir is provided. The volume pumped is determined by counting the number of fills of the reservoir made during a pumping phase. A less expensive pump may be used whilst maintaining an accurate determination of the volume pumped.

1 . Apparatus for pumping a fluid in medical equipment comprising a pump, having an inlet and an outlet, a reservoir divided into at least two chambers, means for selectively fluidly connecting the outlet of the pump to selectively one of the at least two chambers wherein each chamber is connected by means configured to selectively couple the chamber to a fluid outlet of the apparatus and a division for dividing the reservoir into the two chambers moveable to vary the volume of the chambers such that fluid being pumped into a first at least one of the at least two chambers increases the volume of the first of the at least one of the at least two chambers and decreases the volume of the at least one other of the at least two chambers by movement of the division. 
     
     
         2 . Apparatus as claimed in  claim 1 , wherein the division is provided by a moving wall. 
     
     
         3 . Apparatus as claimed in  claim 2  wherein the wall is formed by a flexible membrane. 
     
     
         4 . Apparatus as claimed in  claim 3  wherein the flexible membrane is resiliently deformable. 
     
     
         5 . Apparatus as claimed in  claim 1  wherein selectively operable valves are provided configured to control the filling and emptying of the chambers. 
     
     
         6 . Apparatus as claimed in  claim 5  wherein a first pair of valves is associated with a first chamber and a second pair of valves is associated with a second chamber. 
     
     
         7 . Apparatus as claimed in  claim 6  wherein valves of the pairs are configured to open and close in a synchronised manner with valves of the other pair. 
     
     
         8 . Apparatus as claimed in  claim 7  wherein the valves operate under processor control. 
     
     
         9 . Apparatus as claimed in  claim 7 , wherein the valves are configured such that a first valve of the first pair opens when a first valve of the second pair closes and a second valve of the first pair closes when a second valve of the second pair opens. 
     
     
         10 . Apparatus as claimed in  claim 1  comprising sensors for providing an output for determining when the division has moved to a predetermined extent. 
     
     
         11 . Apparatus as claimed in  claim 10  wherein the sensors determine when the reservoir has been filled. 
     
     
         12 . Apparatus as claimed in  claim 11 , wherein the sensors are located on an internal wall of the reservoir to determine when the division has made contact with or is within the proximity of the internal wall. 
     
     
         13 . A dialysis machine comprising apparatus as claimed in  claim 1  wherein the fluid is a dialysate. 
     
     
         14 . Apparatus for pumping a fluid in medical equipment comprising a pump, having an inlet and an outlet, a reservoir divided into at least two chambers, means for selectively fluidly connecting the outlet of the pump to selectively one of the at least two chambers wherein each chamber is connected by means configured to selectively couple the chamber to a fluid outlet of the apparatus and a division for dividing the reservoir into the two chambers moveable to vary the volume of the chambers such that fluid being pumped into a first at least one of the at least two chambers increases the volume of the first of the at least one of the at least two chambers and decreases the volume of the at least one other of the at least two chambers by movement of the division. 
     
     
         15 . Apparatus for metering a fluid in medical equipment comprising providing one or more chambers each of a variable volume configured in use for connection to a pump for providing a fluid flow to one or more chambers, means to direct the flow into and out of the one or more chambers wherein the one or more chambers have a volume which is variable. 
     
     
         16 . Apparatus as claimed in  claim 15  wherein the one or more chambers have a volume which is determined by a piston within a cylinder. 
     
     
         17 . Apparatus as claimed in  claim 16  wherein respective pistons of respective chambers are operable in a synchronous manner. 
     
     
         18 . Apparatus as claimed in  claim 17  comprising a valve arrangement configured such that wherein when a first chamber is filled the other chamber is emptied. 
     
     
         19 . Apparatus as claimed in  claim 16  wherein the swept volume of the piston within the chamber is variable. 
     
     
         20 . Apparatus as claimed in  claim 19  wherein two or more pistons are linked by a common piston rod to be driven in a synchronous manner. 
     
     
         21 - 23 . (canceled)